Large scale farming involves the use of power-driven assemblies of cultivation equipment to allow for cultivating and planting fields faster, more efficiently, and with less expenditure of resources. In many cases, the equipment, such as tillage equipment, includes a frame or platform that is towed behind a powered vehicle, such as a tractor. These equipment frames can be raised or lowered in relation to supports, typically wheels, in order to bring the tools in contact with the ground or crops at an appropriate height. Maintaining an appropriate height can be an important factor. For example, in planting, seed depth impacts when the plants will germinate and subsequently grow. This can determine when a crop matures and can have an impact on yield or the like.
The raising and lowering of the equipment frame can be handled by hydraulic or similar systems provided on the equipment (here, the term “hydraulics” is intended to include both air and oil types). A disadvantage of using hydraulic systems is the tendency to leak fluid. In these systems, the seals required to separate the pressurized hydraulic fluid from the atmosphere can wear and leaks may occur. Further, when the pressure within the hydraulic system is fluctuating due to differing pressures from the farm implements and the like, additional stresses are placed on the mechanical components of the hydraulic systems, which increase the likelihood of breakdown. If there is a leak or breakdown, the hydraulic system will not be able to maintain or change the height of the frame.
Some conventional systems make use of mechanical stops or the like to maintain height if, for example, the hydraulics fail or are overloaded. However, systems making use of a mechanical stop can be difficult to adjust to a preferred height or depth because they need to be adjusted under a load, whether due to the hydraulics or because the farm implements are in a lowered position or the like. In these systems, the hydraulics typically need to be depressurized before the mechanical stop can be set.
As such, there is need for an improved depth control for height adjustment systems.